1. Field of the Invention
The invention relates to a method of fabricating semiconductor components with electrodes and terminals in which a silicon semiconductor wafer with at least one pn-junction is first prepared. Thereafter, at least one side of the wafer is etched with a grid pattern to cut grooves penetrating through the pn-junction, thereby forming mesas with concave lateral surfaces. The exposed lateral surfaces of the mesas are then provided with passivating coatings and the wafer is split along the grooves.
The method is particularly, but not exclusively, suited to the production of thyristors with central gates, as are known from DT-PS No. 1,132,247 for example.
2. Description of the Prior art
In a known method of the type discussed above, the etching process for producing the mesas leads naturally to concave lateral surfaces, the upper edges of the grooves being separately etched in order to produce a convex portion on the lateral surfaces of each mesa structure at the point of emergence of the pn-junction at the surface (DT-OS No. 2,536,108). These measures serve advantageously to raise the inverse breakdown voltage and desirably to produce negative chamfering of the individual component, i.e., for slices parallel to the pn-junction or the wafer face there is a decrease in cross section towards the zones of lower resistivity or the more strongly doped zones (cf. also the definition in DT-AS No. 1,281,584). In the known case (DT-OS No. 2,536,108) the individual elements after further treatment, e.g. glass passivation of the exposed mesa surfaces, are detached by cutting them apart or by etching away the other side of the wafer. The individual semiconductor chips which are to be made into semiconductor components with electrodes and terminals, must then separately and sequentially, i.e. one after another in serial production, undergo the necessary contacting processes, such as metallization to make solderable ohmic contacts, and terminal soldering. In addition, in the prior art, the rounding of the mesa edges is insufficient, resulting in an angular boundary or a merely rounded corner at the intersections of the grooves.